[glibc] debug: Add fortify dprintf tests

[Adhemerval Zanella <azanella@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=121aad59dea8431cae5cd3efb6ba588d0ddc52b4

commit 121aad59dea8431cae5cd3efb6ba588d0ddc52b4
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Thu Dec 21 15:59:17 2023 -0300

    debug: Add fortify dprintf tests
    
    Similar to other printf-like ones.
    
    Checked on aarch64, armhf, x86_64, and i686.
    Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

Diff:
---
 debug/tst-fortify.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/debug/tst-fortify.c b/debug/tst-fortify.c
index 5cd9d22feb..888eae25ad 100644
--- a/debug/tst-fortify.c
+++ b/debug/tst-fortify.c
@@ -59,6 +59,8 @@
 
 static char *temp_filename;
 
+static int temp_fd_dprintf;
+
 static void
 do_prepare (int argc, char *argv[])
 {
@@ -76,6 +78,13 @@ do_prepare (int argc, char *argv[])
       unlink (temp_filename);
       exit (1);
     }
+
+  temp_fd_dprintf = create_temp_file ("tst-chk2.", NULL);
+  if (temp_fd_dprintf == -1)
+    {
+      printf ("cannot create temporary file: %m\n");
+      exit (1);
+    }
 }
 #define PREPARE do_prepare
 
@@ -901,6 +910,10 @@ do_test (void)
       || n1 != 1 || n2 != 2)
     FAIL ();
 
+  if (dprintf (temp_fd_dprintf, "%s%n%s%n", str2, &n1, str2, &n2) != 2
+      || n1 != 1 || n2 != 2)
+    FAIL ();
+
   strcpy (buf2 + 2, "%n%s%n");
   /* When the format string is writable and contains %n,
      with -D_FORTIFY_SOURCE=2 it causes __chk_fail.  */
@@ -914,6 +927,11 @@ do_test (void)
     FAIL ();
   CHK_FAIL2_END
 
+  CHK_FAIL2_START
+  if (dprintf (temp_fd_dprintf, buf2, str2, &n1, str2, &n1) != 2)
+    FAIL ();
+  CHK_FAIL2_END
+
   /* But if there is no %n, even writable format string
      should work.  */
   buf2[6] = '\0';
@@ -1263,6 +1281,10 @@ do_test (void)
   snprintf (buf, buf_size, "%3$d\n", 1, 2, 3, 4);
   CHK_FAIL2_END
 
+  CHK_FAIL2_START
+  dprintf (temp_fd_dprintf, "%3$d\n", 1, 2, 3, 4);
+  CHK_FAIL2_END
+
   int sp[2];
   if (socketpair (PF_UNIX, SOCK_STREAM, 0, sp))
     FAIL ();